Digestion Continues

Peristaltic motions (rhythmical muscular contractions) assist the mixing of
nutrients inside the stomach and direct them toward the pyloric valve.
1) Peristaltic waves move towards the stomach’s mouth (pilor).
2) The most powerful peristalsis and mixing process takes places
near the stomach’s mouth.
3) The pyloric end of the stomach acts like a pump.
It permits part of the nutrients to enter the duodenum,
and keeps back the rest, sending it on in small parcels.

Food in the stomach, now turned into a gelatinous paste, is forwarded from the duodenum through a one-way valve to the small intestine, an organ only 3 centimeters (1.18 inches) in diameter but more than 7 meters (23 feet) long. This 7-meter (23-foot) tube has been folded, squeezed and packaged into the abdomen of every human being. The miracle is not limited to this packaging, however. Vital phenomena take place inside this narrow enclosure.

Although a large part of the food is broken down in the stomach, some of it remains in the stomach, not broken down into its smallest components. These still-undigested foods that leave the stomach also reach the small intestine shortly afterwards. For example, fats are hard to digest, being very large molecules and indissoluble in water. For that reason, fat digestion occurs not in the stomach, but in the small intestine.

At this point, the pancreas and the liver go into action. These two organs send a special fluid into the small intestine, with the help of a channel or duct.

The liver is apparently aware that the stomach cannot break down fats. At the same time, it possesses the chemical formula for a special compound. As soon as fatty foods reach the small intestine, the liver releases the liquid it has prepared and stored, at exactly the right time and place.

The function of this secretion, known as bile, is not limited to breaking down fats. It also helps with the absorption of fats broken down by the small intestine. In addition, it contains special chemical compounds that permit the intestines to absorb vitamins, and is also an antiseptic that kills harmful bacteria remaining in the intestine.

Gall subjects the fats in foodstuffs reaching the small intestine to a preliminary process that will increase the effect of the pancreatic secretion. The various enzymes contained in pancreatic fluid assist not only in the digestion of fats, but also of starch and proteins. There are also large numbers of glands in the mucosa covering the wall of the small intestine that secrete various enzymes that play an important role in the digestion of foods sufficiently broken down. Most of the food in the small intestine gets broken down some 3 to 5 hours after eating. In this way, carbohydrates are reduced to simple sugars, proteins into amino acids, and fats into glycerol and fatty acids, ready for assimilation. The cells in the small intestine absorb these molecules and then release these nutrients into the bloodstream.

When the foodstuff is ready to leave the small intestine, no nutrients remain apart from water and certain vitamins.

CELLS THAT PRODUCE AN ELECTRIC CURRENT

Various mechanisms permit the foods to be transmitted along the digestive tract. One is the involuntary contraction of the muscles in the intestines. Thanks to the rhythmic contraction of these muscles, foodstuffs always progress in one direction only. But why? A team of researchers led by Jan Huizinga of McMaster University in Canada investigated this subject, examining the cells that bring about this one-way movement. They used micro-electrodes located along the digestive tract to establish that the so-called interstitial cells of Cajal set up a constant, regular electrical current. This current permits the muscles, that surround the intestine wall, to contract constantly. However, the presence of an electrical current is not sufficient for this mechanism to function. The current must also be set up with a flawless rhythm. Within the intestines, therefore, the cells of Cajal set up a web that allows them to give off electrical impulses at the same rhythm. (Science et Vie, September, 1998).

Thanks to this flawless mechanism, the things you eat remain in the digestive tract and are turned into a form your body can make use of. Were it not for the rhythmical electrical impulses established by the cells of Cajal, the muscles in your intestines would not contract in harmony, which could lead to the food you eat heading back into your throat instead of traveling onward. However, apart from in certain cases of sickness, we are never faced with this disagreeable phenomenon. As this example shows, the system created by Allah in the human body is flawless in every respect. Thanks to this blessing, we are all able to carry on with our lives.